This summer’s fourth heat wave is expected to begin on Wednesday, with local temperatures rising to 40 degrees.
Similar temperatures are expected in Spain.
Dozens of communities remain threatened by bushfires, which have forced more than 70,000 people from their homes over the past week.
Spain has ended some evacuation orders, allowing about 44,000 people to return home or escape quarantine.
The Madrid region has been particularly hard hit, but Prime Minister Pedro Sánchez said although there were very difficult times and days ahead, light was starting to appear “at the end of the tunnel.”
In neighboring Portugal, 400 firefighters were battling a massive fire that broke out on three fronts in the eastern province of Guarda.
The French city of Bordeaux is not currently under threat, officials said, despite the fact that one of Monday’s wildfires started just 15 kilometers (9 miles) from the city’s perimeter.
However, Commander Rémi Lasoreille, who is leading the fire response in the Gironde region, is still worried.
“We are afraid of the impact on Bordeaux and the metropolitan area,” he said. The air quality in the city has also deteriorated significantly.
A holidaymaker from Essex told the BBC: “By Sunday evening everything was starting to empty out,” adding that the air was “really smoky” with bits of ash. “It was eerie and very sad because people were staying indoors.”
